Blaine shared this build that combined a CJ-5 and a GMC bed was featured a few years ago on Autowrecking.com. It was a product of necessity; he builder had an old CJ-5 and needed a truck.
https://www.autowrecking.com/blog/custom-1957-willys-jeep-CJ5
That’s pretty cool. Wish we could see more pics of the bed itself; how and where they chopped it to fit.